Electronic shelf assembly incorporating spring loaded circuit pack latch rails

FIELD OF THE DISCLOSURE

The present disclosure relates generally to an electronic shelf assembly, such as that used in the optical networking field and others. More specifically, the present disclosure relates to an electronic shelf assembly incorporating spring loaded circuit pack latch rails.

BACKGROUND OF THE DISCLOSURE

In the optical networking field and others, electronic components, or electronic circuit packs or cards, are typically inserted into an electronic shelf assembly, or electronic chassis or rack, including a backplane by which electrical connections are made. Typically, these electronic circuit packs or cards are inserted into the electronic shelf assembly in a side-by-side vertical (or horizontal) configuration, and each circuit pack or card is secured within the shelf assembly by one or more latches that engage latch rails coupled to the shelf assembly. When inserted, connectors on the back portion of each circuit pack engage connectors on the backplane, completing the desired electrical connections. In high speed optical networking systems, for example, it is desirable that these connectors are fully engaged (i.e., “fully seated” or “bottomed out”), given a range of manufacturing and assembly tolerances associated with the various mechanical structural components. Thus, the connectors must have sufficient “wipe” and be able to accommodate this range of manufacturing and assembly tolerances.

As optical networking system speeds continue to increase, connectors (and the associated pins) are becoming shorter and shorter, to improve signal integrity, and connector “wipe” is decreasing, resulting in tighter and tighter manufacturing and assembly tolerances. This translates into increased expense, as conventional manufacturing technologies must be abandoned. Conventional electronic shelf assemblies, circuit packs, and latches do not adequately address this issue.

Thus, what is still needed in the art is an electronic shelf assembly that minimizes the issue of connector mating tolerance; consistently “seating” and “bottoming out” shortened connectors, while allowing a circuit pack to be properly secured by conventional latch(es) and accommodating a range of manufacturing and assembly tolerances.

BRIEF SUMMARY OF THE DISCLOSURE

In various exemplary embodiments, the present disclosure provides an electronic shelf assembly that incorporates spring loaded circuit pack latch rails. The spring mechanism utilized with each latch rail is pre-loaded in excess of the given connector insertion force and the connector will “bottom out” before the spring mechanism is compressed further. Once the connector is “bottomed out,” the latch force will exceed the pre-load on the spring mechanism, and the latch rail will move or deflect. This movement or deflection of the latch rail absorbs the manufacturing and assembly tolerances associated with the electronic shelf assembly, circuit pack, and latches, while properly securing the circuit pack in the electronics shelf assembly. In this manner, excess forces on the connectors are avoided.

In one exemplary embodiment, the present disclosure provides an electronic shelf assembly configured to selectively receive a circuit pack including a pivotable handle incorporating a retention hook, the electronic shelf assembly including: a shelf assembly housing configured to selectively receive the circuit pack; a support rail coupled to the shelf assembly housing; a latch rail member movably coupled to the support rail and defining a recess configured to selectively receive and retain the retention hook of the pivotable handle of the circuit pack, thereby selectively securing the circuit pack within the shelf assembly housing; and a spring mechanism coupled to the latch rail member and the support rail, wherein the spring mechanism allows for relative movement of the latch rail member with respect to the support rail while biasing the latch rail member towards the support rail, thereby selectively biasing the circuit pack into the shelf assembly housing. The shelf assembly housing includes a backplane including a connector configured to selectively engage a connector of the circuit pack. The support rail includes a recess configured to selectively engage a rail of the circuit pack. The latch rail member includes a substantially planar portion and a retention post. The retention post of the latch rail member is disposed through one or more holes formed through the support rail, thereby movably coupling the latch rail member to the support rail. The latch rail member also includes one or more guide pins. The one or more guide pins of the latch rail member are disposed through one or more holes formed through the support rail, thereby preventing rotation of the latch rail member with respect to the support rail. The spring mechanism includes a linear spring disposed about the retention post of the latch rail member on a side of the support rail opposite the latch rail member. The linear spring is secured to the retention post using a washer and a nut. The spring mechanism is pre-loaded in excess of a predetermined connector insertion force associated with the electronic shelf assembly and the circuit pack.

In another exemplary embodiment, the present disclosure provides a latch rail assembly configured to be coupled to an electronic shelf assembly and selectively receive a circuit pack including a pivotable handle incorporating a retention hook, the latch rail assembly including: a support rail configured to be coupled to the electronic shelf assembly; a latch rail member movably coupled to the support rail and defining a recess configured to selectively receive and retain the retention hook of the pivotable handle of the circuit pack; and a spring mechanism coupled to the latch rail member and the support rail, wherein the spring mechanism allows for relative movement of the latch rail member with respect to the support rail while biasing the latch rail member towards the support rail. The support rail includes a recess configured to selectively engage a rail of the circuit pack. The latch rail member includes a substantially planar portion and a retention post. The retention post of the latch rail member is disposed through one or more holes formed through the support rail, thereby movably coupling the latch rail member to the support rail. The latch rail member also includes one or more guide pins. The one or more guide pins of the latch rail member are disposed through one or more holes formed through the support rail, thereby preventing rotation of the latch rail member with respect to the support rail. The spring mechanism includes a linear spring disposed about the retention post of the latch rail member on a side of the support rail opposite the latch rail member. The linear spring is secured to the retention post using a washer and a nut. The spring mechanism is pre-loaded in excess of a predetermined connector insertion force associated with the electronic shelf assembly and the circuit pack.

In a further exemplary embodiment, the present disclosure provides a latch rail assembly configured to be coupled to an electronic shelf assembly and selectively receive a circuit pack including a pivotable handle incorporating a retention hook, the latch rail assembly including: a support rail; a latch rail member movably coupled to the support rail and defining a recess; and a spring mechanism coupled to the latch rail member and the support rail, wherein the spring mechanism allows for relative movement of the latch rail member with respect to the support rail while biasing the latch rail member towards the support rail. The latch rail assembly also includes a plurality of additional latch rail members and spring mechanisms coupled to the support rail along a length thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like assembly components, as appropriate, and in which:

<figref idref="DRAWINGS">FIG. 1</figref> is a partially exploded perspective view illustrating one exemplary embodiment of the spring loaded circuit pack latch rail assembly of the present invention;

<figref idref="DRAWINGS">FIG. 2</figref> is a partially exploded planar view illustrating one exemplary embodiment of the spring loaded circuit pack latch rail assembly of the present invention;

<figref idref="DRAWINGS">FIG. 3</figref> is a planar view illustrating one exemplary embodiment of the spring loaded circuit pack latch rail member of the present invention;

<figref idref="DRAWINGS">FIG. 4</figref> is a partial cross-sectional view illustrating one exemplary embodiment of the spring loaded circuit pack latch rail assembly of the present invention;

<figref idref="DRAWINGS">FIG. 5</figref> is a planar and perspective view illustrating exemplary embodiments of an electronic shelf assembly and an electronic circuit pack, respectively, used in conjunction with the spring loaded circuit pack latch rail assembly of the present invention;

<figref idref="DRAWINGS">FIG. 6</figref> is a perspective view illustrating one exemplary embodiment of an electronic circuit pack latch assembly used in conjunction with the spring loaded circuit pack latch rail assembly of the present invention; and

<figref idref="DRAWINGS">FIG. 7</figref> is a planar view illustrating one exemplary embodiment of an electronic circuit pack latch assembly used in conjunction with the spring loaded circuit pack latch rail assembly of the present invention.

DETAILED DESCRIPTION OF THE DISCLOSURE

Again, in various exemplary embodiments, the present disclosure provides an electronic shelf assembly that incorporates spring loaded circuit pack latch rails. The spring mechanism utilized with each latch rail is pre-loaded in excess of the given connector insertion force and the connector will “bottom out” before the spring mechanism is compressed further. Once the connector is “bottomed out,” the latch force will exceed the pre-load on the spring mechanism, and the latch rail will move or deflect. This movement or deflection of the latch rail absorbs the manufacturing and assembly tolerances associated with the electronic shelf assembly, circuit pack, and latches, while properly securing the circuit pack in the electronics shelf assembly. In this manner, excess forces on the connectors are avoided.

Referring now specifically to <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, in one exemplary embodiment, the latch rail assembly <b>10</b> of the present invention includes a support rail <b>12</b> that is rigidly mounted to a conventional shelf assembly housing <b>14</b> (<figref idref="DRAWINGS">FIG. 5</figref>) using screws, rivets, pins, and/or the like. Such shelf assembly housings <b>14</b> are well known to those of ordinary skill in the art. The support rail <b>12</b> includes a plurality of slots or recesses <b>16</b>, each configured to receive a rail <b>18</b> (<figref idref="DRAWINGS">FIG. 5</figref>) associated with a corresponding circuit pack <b>20</b> when the circuit pack <b>20</b> is disposed within the shelf assembly housing <b>14</b>, by, for example, sliding the circuit pack <b>20</b> into the shelf assembly housing <b>14</b>. Accordingly, the latch rail assembly <b>10</b> can be utilized above and/or below, or on either side of, the circuit pack(s) <b>20</b>, as the configuration of the shelf assembly housing <b>14</b> dictates. As alluded to above, one or more connectors disposed on the back portion of each circuit pack <b>20</b> engage one or more connectors associated with the backplane of the shelf assembly housing <b>14</b> when the circuit pack(s) <b>20</b> are disposed within the shelf assembly housing <b>14</b>, thereby completing the desired electrical connections.

A plurality of latch rail members <b>22</b> are movably coupled to the support rail <b>12</b>. Each of the plurality of latch rail members <b>22</b> includes one or more recesses or slots <b>24</b>, or the like, that is/are configured to receive and retain one or more hooks or protrusions <b>26</b> (<figref idref="DRAWINGS">FIGS. 6 and 7</figref>), or the like, associated with the corresponding circuit pack <b>20</b> when the circuit pack <b>20</b> is disposed within the shelf assembly housing <b>14</b> and secured. In general, such recesses or slots <b>24</b> and hooks or protrusions <b>26</b> are well known to those of ordinary skill in the art as a means for securing a circuit pack <b>20</b> within a shelf assembly housing <b>14</b>. Specifically, each circuit pack <b>20</b> includes a faceplate <b>28</b> (<figref idref="DRAWINGS">FIGS. 6 and 7</figref>) including a pivotable handle <b>30</b> (<figref idref="DRAWINGS">FIGS. 6 and 7</figref>) at each end. When these pivotable handles <b>30</b> are actuated, the associated hook(s) or protrusion(s) <b>26</b> are deployed into the recess(es) or slot(s) <b>24</b> of the corresponding latch rail member <b>22</b>, and the circuit pack <b>20</b> is biased into and secured within the shelf assembly housing <b>14</b>, thereby ensuring the proper electrical connection between the circuit pack <b>20</b> and the backplane. Advantageously, this electrical connection is not disrupted by vibrations or the like that the shelf assembly housing <b>14</b> is often subjected to.

It should be noted that, although a plurality of latch rail members <b>22</b> are coupled to each support rail <b>12</b> in this exemplary embodiment, with each latch rail member <b>22</b> including a pair of recesses <b>24</b> for receiving a pair of hooks <b>26</b>, it will be readily apparent to those of ordinary skill in the art that a single latch rail member <b>22</b> including a plurality of recesses <b>24</b> could be used to retain and secure a plurality of circuit packs <b>20</b> utilizing any number of hooks <b>26</b>. One advantage to utilizing a plurality of latch rail members <b>22</b> coupled to each support rail <b>12</b> is that the force applied to each connector can be individualized, ensuring that each connector is appropriately “bottomed out.” It should also be noted that this latch rail assembly configuration can be utilized at one or both ends of each circuit pack <b>20</b>. Typically, the components of the latch rail assembly <b>10</b> are manufactured from a metal, a hardened plastic, or another similarly rigid material.

Referring now specifically to <figref idref="DRAWINGS">FIGS. 1-3</figref>, each latch rail member <b>22</b> includes a substantially planar portion <b>32</b> in which the recesses or slots <b>24</b> are formed. A retention post <b>34</b> is coupled to this substantially planar portion <b>32</b>. When the latch rail member <b>22</b> is coupled to the support rail <b>12</b>, this retention post <b>34</b> passes through one or more holes manufactured into the support rail <b>12</b>. One or more guide pins <b>36</b> are also coupled to the substantially planar portion <b>32</b> and engage one or more holes manufactured into the support rail, thereby preventing rotation of the substantially planar portion <b>32</b> with respect to the support rail <b>12</b>. It will be readily apparent to those of ordinary skill in the art that various components of the latch rail member <b>22</b> can be integrally formed. The end of the retention post <b>34</b> that passes through the support rail <b>12</b> includes threads <b>38</b> and a washer stop <b>40</b> for receiving a washer <b>42</b> and a nut <b>44</b>. When fully assembled, the washer stop <b>40</b> is disposed a predetermined distance from the corresponding surface of the support rail <b>12</b>, such that a gap is formed for the placement of a spring <b>46</b> (<figref idref="DRAWINGS">FIGS. 1 and 2</figref>).

The spring gap and spring <b>46</b>, which may be a linear compression spring, a bushing, or the like, are selected such that the spring mechanism utilized with each latch rail member <b>22</b> is pre-loaded in excess of the given connector insertion force and the connector will “bottom out” before the spring mechanism is compressed further. Once the connector is “bottomed out,” the latch force will exceed the pre-load on the spring mechanism, and the latch rail member will move or deflect. This movement or deflection of the latch rail member <b>22</b> absorbs the manufacturing and assembly tolerances associated with the shelf assembly housing <b>14</b> (<figref idref="DRAWINGS">FIG. 5</figref>), circuit pack <b>20</b> (<figref idref="DRAWINGS">FIG. 5</figref>), and pivotable handle <b>30</b> (<figref idref="DRAWINGS">FIGS. 6 and 7</figref>), while properly securing the circuit pack <b>20</b> in the shelf assembly housing <b>14</b>. In this manner, excess forces on the connectors are avoided. It will be readily apparent to those of ordinary skill in the art that the location and type of spring or bushing can be varied, provided that the spring or bushing biases the latch rail member <b>22</b> in its original position prior to a sufficient force being exerted upon it by the corresponding circuit pack <b>20</b>, at which point the latch rail member <b>22</b> will move or deflect predictably. A linear compression spring is preferred in this capacity due to its very predictable characteristics.

<figref idref="DRAWINGS">FIG. 4</figref> more clearly illustrates the configuration of the latch rail assembly <b>10</b> of the present invention. Specifically, the substantially planar portion <b>32</b> of the latch rail member <b>22</b> is coupled to the retention post <b>34</b>, which passes through the support rail <b>12</b>. The washer <b>42</b> and nut <b>44</b> engage the threads <b>38</b> and washer stop <b>40</b> of the retention post <b>34</b> on the back side of the support rail <b>12</b>, opposite the substantially planar portion <b>32</b> of the latch rail member <b>22</b>. When fully engaged, the washer <b>42</b> and back surface of the support rail <b>12</b> define the spring gap, or pre-load gap, in which the linear compression spring <b>46</b> is disposed. Again, the spring <b>46</b> is not compressed beyond the pre-load, and the substantially planar portion <b>32</b> of the latch rail member <b>22</b> does not move or deflect, until the associated connector is “bottomed out” and the latch force exerted on the substantially planar portion <b>32</b> of the latch rail member <b>22</b> exceeds the pre-load of the spring <b>26</b>. By way of example only, this latch force may be about 100 lbs. and the substantially planar portion <b>32</b> of the latch rail member may move or deflect by about 0.1 in., although such specifications are dependent upon the application.

In general, it can be appreciated that the moving or deflecting latch rail member <b>22</b> holds the corresponding circuit pack <b>20</b> and its connector(s) securely against the backplane of the shelf assembly housing <b>14</b>, while accommodating the associated manufacturing and assembly tolerances. The moving or deflecting latch rail member <b>22</b> does not exert extreme forces on these components due to the careful selection of the associated spring <b>46</b>. In this manner, the issues presented by conventional electronic shelf assemblies are addressed, especially as they relate to high-speed optical networking systems and the like.

Although the present disclosure is illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure, are contemplated thereby, and are intended to be covered by the following claims, without limitation.